1. Field of the Invention
The present invention relates to systems control modules, and more particularly, to flight deck panels for aircraft.
2. Background
The flight deck (cockpit) area of an aircraft includes a large number of different types of switches and knobs for controlling different aircraft system functions. Due to the large number of control and indicating devices, they are arranged in modules, encompassing large areas viewable and reachable by the flight crew.
Modules having similar control or indicating functions may be arranged and located similarly in the flight decks of different aircraft, for ease of use by the flight crew. Also, similar switches and knobs, both with respect to look and feel, are provided for similar functions. For example, a flight deck module may incorporate a row of rotary switches, push button switches, or rheostats. A particular panel may or may not incorporate knobs or buttons, and some panels may consist solely of banks of gauges to indicate the status of different flight control systems.
Typical aircraft rotary controls often provide two groups of control knob position signals (two poles) for redundancy. Control knobs have two or more positions that are encoded. Such position signals are often binary encoded. For in-between control knob positions (for example, the control knob may be in a position in-between switch detents), positions indicated by the pole signals often differ. Thus, position detection is inhibited until a valid position is reached (such as when the control knob reaches a detent).
Various methods for implementing rotary knob controls on flight deck modules have been attempted. One conventional method is shown in FIG. 1A, which shows an apparatus 10 for rotary code-based control. A magnet carrier platter 20 carries magnets 30 on its surface. The magnets 30 are placed in a radial orientation. Hall-effect sensors 40 are mounted near the magnet carrier platter 20 at positions corresponding to the location of the magnets 30. Using a hall-effect sensor 40, a voltage is generated transversely to the current flow direction, if a magnetic field is applied perpendicularly to the magnet carrier platter 20.
Voltage is generated by the effect of an external magnetic field acting perpendicularly to the direction of current. A hall-effect sensor 40 senses the magnet fields produced by magnets 30 and generate an indicator position signal in response thereto.
As shown in FIG. 1B, redundancy is often attempted by using two magnet carrier platters 20. A large number of magnets 30 are oriented radically on the surface of one of the magnet carrier platter 20. A large number of magnets 32 are also oriented radially on the surface of another magnet carrier platter 20. Each of the magnets 32 is in vertical alignment with each of the magnets 30 for redundancy.
Such, for example, radial orientation of magnets 30 has several disadvantages. Two magnet carrier platters are needed, thus increasing overall cost of flight deck module controls. Costs are also high since many magnets are used to span the magnet carrier platter radius. The radial orientation of the magnets also requires larger magnet carrier platters due to crowding at the location of the magnets at the smaller radial positions nearer the center of the magnet carrier platters. Because the radial orientation often involves crowding at smaller radii, invalid codes (such as in-between position codes) are more likely to be produced for in-between positions.
Therefore, what is desired is a system that can code rotary positions at lower cost, with smaller parts, and with a lesser likelihood of producing invalid codes for in-between positions.